Easy launch due to good weather, due to high speed jetstream we had the option of either a quick flight with certain landing in the North Sea or a European floater. We elected the quick flight to allow for the longest period of time within range of ground nodes. The payload was launched under an 800g Pawn balloon with an additional old 434 RTTY tracker 'X0'. While the node performed on the ground it very quickly lost contact with the ground nodes on launch. Packets were received for a few minutes and then stopped coming through. Packets were then received by DB02 and DB03 as the payload passed over. Overall the range was very poor with the node reporting that it had only received one packet. At the launch site we investigated the poor performance and found that our ground nodes were regularly freezing up (and so may have missed packets). Looking on a funcube dongle showed a significant interference.
The suspicion is that the noise is triggering the rx function within the receiver and this is locking up. If the ground stations are getting caught by local interference there is a high chance that an airborne node will be in the same situation.
To test the situation further we went on to launch a second node (BALL1) under a 100g Totex balloon. This showed a very similar pattern of quickly going out of range and then as it passed over the DB02/DB03 network passing some packets through and then disappearing. Unfortunately there were no balloon to balloon communications.
The graph below shows the RSSI from the DB02 node, it is possible to identify both AH3 and BALL1 passing over this node and communicating with it.